J/A+A/635/A43ivo://CDS.VizieR/J/A+A/635/A43doi:10.26093/cds/vizier.36350043CDSReinhold T.Hekker S.2020-05-06T08:28:51Z2020-03-04T07:40:26ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.frvariable-starsapparent-magnitudeRotation period measurements of stars observed with the Kepler mission have revealed a lack of stars at intermediate rotation periods, accompanied by a decrease of photometric variability. Whether this so-called dearth region is a peculiarity of stars in the Kepler field, or reflects a general manifestation of stellar magnetic activity, is still under debate. The K2 mission has the potential to unravel this mystery by measuring stellar rotation and photometric variability along different fields in the sky. Our goal is to measure stellar rotation periods and photometric variabilities for tens of thousands of K2 stars, located in different fields along the ecliptic plane, to shed light on the relation between stellar rotation and photometric variability. We use Lomb-Scargle periodograms, auto-correlation and wavelet functions to determine consistent rotation periods. Stellar brightness variability is assessed by computing the variability range, R_var_, from the light curve. We further apply Gaussian mixture models to search for bimodality in the rotation period distribution. Combining measurements from all K2 campaigns, we detect rotation periods in 29860 stars. The reliability of these periods was estimated from stars observed more than once. We find that 75-90% of the stars show period deviation smaller than 20% between different campaigns, depending on the peak height threshold in the periodograms. For effective temperatures below 6000K, the variability range shows a local minimum at different periods, consistent with an isochrone age of ~750Myr. Additionally, the rotation period distribution shows evidence for bimodality, although the dearth region in the K2 data is less pronounced compared to the Kepler field. The period at the dip of the bimodal distribution shows good agreement with the period at the local variability minimum. We conclude that the rotation period bimodality is present in different fields of the sky, and is hence a general manifestation of stellar magnetic activity. The reduced variability in the dearth region is interpreted as a cancelation between dark spots and bright faculae. Our results strongly advocate that the role of faculae has been underestimated so far, suggesting a more complex dependence of the brightness variability on the rotation period.2020A&A...635A..43Rhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/635/A43CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toIV/34 : K2 Ecliptic Plane Input Catalog (EPIC) (Huber+, 2017)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/635/A43https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/635/A43http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/635/A43https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/635/A43https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/635/A43http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/635/A43GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/635/A43/table2 (Parameter table)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/635/A43/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/635/A43/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/635/A43/table2?GETtext/xml+votable180.050000true93.4523726.789140.0055555555555555563/73 4/17 19 22 28-29 65 267 270-271 282 289 304 1082 1127 1133 1144 1146 1154 1161 1168-1169 1171 1512 1514-1515 1591 1597 1603 1606 1612 1615 1640-1641 1686-1687 1692-1693 1715-1716 1718 1730 1814 1824 2770 2772 5/67 73 75 82 85 92 94-95 100-102 120 256-258 264 268 272 1063 1067 1073-1075 1077-1079 1122 1132 1134 1155 1164-1165 1167 1204 1220 1222 1224-1226 4287 4322-4323 4326-4327 4332 4334 4345 4347 4499 4502-4504 4506-4507 4528-4529 4531 4537 4540-4541 4543 4546 4556 4582-4583 4588 4590 4608 4612-4614 4620 4622-4623 4627 4629 4631 4634 4641-4643 4652-4654 4656-4658 4660 4664-4665 4680-4681 4683 4688 4690 4696 4698-4699 4708-4709 5870-5871 5877 5879 5882-5885 5887 5987 5991 5996 5999 6009-6010 6014 6026-6027 6030 6042 6055 6072 6074 6084-6085 6096-6097 6356-6358 6361 6363 6387 6394 6396-6398 6401-6404 6406-6407 6409 6411 6418-6419 6422-6423 6428 6430-6431 6433 6436-6437 6439 6452-6454 6474 6498 6528-6529 6531 6537-6539 6542 6544 6568-6570 6572-6574 6576 6725 6727 6733 6735-6736 6738-6739 6743 6757 6761 6763-6764 6776 6780 6848-6849 6851-6852 6854-6855 6857 6859 6870 6876-6878 6884-6885 6887 6896-6897 6900 6914-6915 6926 6944-6946 6952 7210 7212 7224 7233 7238-7239 7244-7245 7248 7250-7251 7253-7254 7260-7262 7300 7302 7304-7306 7310 7312 7314 7323 7329 7332 7337-7338 7344 7424 7682 10717 10719 10733 10735-10738 10744 10747 10750-10751 11039 11063 11069 11075-11077 11079 11087 11092-11093 11096 11098 11100-11101 11104 11106-11109 11111-11113 11115 11117 11119-11120 11122 11128-11130 11182 11192 11194 12006-12007 12012 12015-12017 12023 12026-12027 12030 12125 12127 6/260-261 263 265-267 289 291 320 322-323 334-337 339 344 346 349 351 373-375 388-389 391 397 399 412-413 415 437 439 484-486 496 1036-1037 1039 1061 1063-1066 1076-1077 1092 1094-1098 1100-1102 4223 4245-4247 4250-4251 4262-4263 4290-4291 4304 4306-4307 4480 4482-4483 4492 4494-4495 4506 4534 4540 4613 4615 4645 4665 4757 4759 4800-4802 4804-4805 4820 4886 4892 4908-4909 4912 4992-4993 17082-17083 17087 17117 17130 17139 17142-17143 17145 17147 17303 17332-17334 17340 17342 17346 17352 17354 17376 17379 17385 17392 17394 17400 17402 17975 17990-17991 18002-18003 18006-18007 18021-18023 18120-18121 18123 18145 18147 18168-18169 18171 18177-18179 18182 18188 18190-18191 18202-18203 18206 18208 18210 18216 18218-18219 18222-18223 18228 18230 18232-18233 18236 18320 18322 18327 18356-18357 18376 18378 18436-18438 18441-18444 18446-18447 18462 18484 18486 18496 18498-18499 18520 18522 18530-18533 18540 18542 18544 18548-18549 18551 18557 18560-18561 18563 18592-18593 18597 18599 18605 18620-18621 18636-18638 18646 18648-18650 18652 18664-18665 18668-18669 18680 18728-18729 18758 18764 18766 18788 18790 18820-18821 18823 18880-18882 18884-18885 19537 19540-19541 19712-19713 19716-19717 23423 23470-23471 23479 23505 23515 23522-23523 23526 23545-23547 23797 23838 23847 23850-23851 23854-23855 23857-23859 23861-23865 23867 23907 23909 23911 23916 23936 23939-23940 23943 23946-23947 23952-23953 23955-23956 23958-23961 23968-23969 23971-23972 23975 23977 23980 23982-23983 23988-23990 23992 23995 24001-24002 24004 24006-24010 24012-24013 24015 24025-24028 24030-24034 24046-24050 24052 24054 24060 24102-24103 24113-24115 24124 24127 24208 24210 24216 24218-24219 24256-24258 24260 24264 24266 24324 24326-24327 24335 24344-24345 24349 24351 24392-24394 24396 24404 24416 24927 25083 25421-25423 25436 25441 25443 25448-25449 25533 25535 25541-25543 25570-25571 25573 25580-25582 25596-25598 25601-25603 25622 25632-25633 25635 25641-25643 25666-25667 25670-25671 25681-25684 25686-25687 25716 25718-25719 25729 25741 25752-25753 25755 25771 25774 25780-25781 25783 25820-25821 25823-25826 25829 25834-25835 25839 25890 25984 25986 25998 26016-26018 26024 26121 26133 26145-26147 26160 26162-26163 26172 26174-26175 26180-26181 26192-26193 26195-26196 26198 26218 26284-26286 26300 26302 26312-26314 26336 26899 26905-26907 26928-26929 26939 26948 26961 26963-26964 26966 26969-26971 27023 27025 27034 27037 27039 27049 27051 27061 27064 27066-27067 27108-27109 27111-27112 27114-27115 27124-27125 27223 27229 27400-27401 27403 27412 27414-27415 27425-27427 27432-27433 27435 27474 27486 27516-27518 27525 27527 27545 27592-27593 27596-27597 27599 27604 27608-27610 27651-27652 27654-27655 27672 27674 27698 27788-27790 27792 27812 28192 28194 28826-28827 28830 28835-28836 28838-28839 28844-28846 28852 28855 28858 28904 28929 28941-28944 28946-28949 28951 28965 28985 28988 28996 28998-28999 29009-29011 29021-29023 29052 29120-29121 29124 29206-29207 29212-29214 29228-29230 29232-29234 29236-29238 29244-29245 29247 29260 29262 29281-29284 29286-29288 29290-29291 29304-29306 29312-29313 29315 29321 29324-29325 29327 29334-29335 29337 29340-29341 29344 29346-29347 29356-29358 29360 29362 29380 29382 29384-29385 29704 29728 29730 30720-30721 30723 30725-30727 30732-30734 30738 30752-30753 42494-42495 42836-42837 42839 42845-42847 42859 42861-42863 42865 42867 42874 42903 42905 42908 42910-42911 42929 42931 42938-42939 42956 42958-42960 42964-42965 42967 42973-42975 42980-42982 42984 42986-42987 42992-42994 42996 42998-42999 44149-44151 44155 44244-44245 44247 44251 44273 44295 44299 44312 44314 44341 44344 44346-44347 44377-44381 44383 44388-44390 44396 44412-44413 44420-44422 44441-44443 44456-44457 44459 44464-44465 44467 44473-44475 44484 44486-44487 44492-44493 44495 44504 44506-44507 44524-44526 44528-44530 44711 44717-44720 44722-44723 44726 44732-44733 44774 44780-44782 44804-44805 44807 44816-44818 44820-44821 44823 44864-44866 48015 48022-48023 48037 48039 48043 48046-48047 48054-48057 48059 48072-48074 48076 48083 48086 48088-48089 48091 48096 48098-48099 48113-48114 48116 48478-48479 48596-48597 48599 48605 48607 48629 48810https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/635/A43?format=asciidefaultJ/A+A/635/A43/table2Parameter tablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintEPICUnique identifier in the K2 input catalogmeta.id;meta.mainlongCampaignK2 observing campaignmeta.noteintTeffEffective temperatureKphys.temperature.effectiveintloggSurface gravitylog(cm**2.s**-1)phys.gravityfloatProtRotation perioddtime.periodfloate_ProtRotation period uncertaintydstat.errorfloatHPeakNormalized peak heightphot.flux;arith.ratiofloatRvar? Variability range%src.var.amplitudefloatnullableKpmagKepler magnitudemagphot.mag;em.optfloatGMAG? Gaia absolute magnitudemagphys.magAbsfloatnullable_RAPositions from EPIC catalog (Huber et al., 2017, IV/34 (right ascension part)degpos.eq.ra;meta.mainindexed_DEPositions from EPIC catalog (Huber et al., 2017, IV/34 (declination part)degpos.eq.dec;meta.mainindexed